1. Field of the Invention.
The present invention relates generally to inclined lift devices for individually transporting passengers in ascending and descending directions along a stairway or other inclined surface. More particularly, the present invention relates to an inclined lift device having a passenger support that is maintained at a preselected constant incline while the passenger support is moved along a curved rail or a rail having varying degrees of inclination.
2. Description of the Prior Art.
Inclined lift devices, such as stairway chairlift devices, are utilized for individually transporting persons who have difficulty in ascending or descending stairs and other inclined surfaces. Typical stairway chairlift devices include a track or rail supported along the inclined surface and a carriage with a passenger support driven along the rail so as to ascend or descend the inclined surface. The rail typically guides movement of the carriage up and down the inclined surface. The rail and the carriage also cooperate to maintain the passenger support and the accompanying passenger at a preselected constant incline angle while the passenger moves up or down the inclined surface to protect the passenger from falling off of the passenger support.
Maintaining the passenger support at a constant incline angle has previously required the development of rail structures unique to each particular inclined surface being ascended or descended by the lift device. For example, different rail configurations are typically required to travel up and over landings, around corners and around curves of various stairways. Each unique rail design consequently requires a corresponding unique carriage adapted to move along the rail at a preselected constant incline angle along the rail. As a result, conventional inclined lift devices have required extensive custom made rails and carriages which are expensive to design, build, install, maintain and re-use.